Field of the Invention
The present invention relates to hypodermic needles used for injecting drugs into parenteral visits and/or removing the contents before or after mixing. Air venting of these vials is provided with this apparatus. Needles used with syringes are found in the general class of "SURGERY." Withdrawal of the fluid contents from vials creates negative pressure problems and this invention is directed to providing vial venting.
Venting of the stoppered vial is desirable and necessary because of the negative pressures developed as and while the fluid is withdrawn from the vial. Constant and continued venting of the vial eliminates this problem of negative pressure. Drawbacks are present in commonly-used and -known procedures. In a procedure using two needle punctures, every time a vial is punctured there is a risk of contamination. It is evident that the fewer times a container needs to be punctured, the more aseptic the interior. It is also to be noted that use of two needles in a stopper of a vial to provide venting is a very clumsy procedure as the vial must be held while securing two needles and syringe which is attached to one of the needle. This procedure requires much manipulation.